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Red Hat Enterprise Linux technology capabilities and limits

What can Red Hat® Enterprise Linux® do? Find out in this quick-glance chart of the supported and theoretical 1 limits of the platform.

Specification

Version 3

Version 4

Version 5

Version 6

Version 7

Maximum logical CPUs 2

x86

16

32

32

32

N/A6

Itanium 2

8

256 [512]

256 [1024]

N/A6

N/A6

x86_64

8

64 [64]

160 [255]

448 [4096]17

768 [5120]18

POWER

8

64 [128]

128

128

768 [2048]20

System z

64 (z900)

64 (z10 EC)

64 (z13)

64 (z13)

256 (z13)

Maximum memory5

x86

64GB3

64GB3

16GB4

16GB4

N/A6

Itanium 2

128GB

2TB

2TB

N/A6

N/A6

x86_64

128GB

256GB [1TB]

1TB

12TB [64TB]15

12TB [64TB]16

POWER

64GB

128GB [1TB]

512GB [1TB]

2TB

32TB21

System z

256GB (z900)

1.5TB (z10 EC)

4TB (z13)

4TB (z13)

10TB (z13)

Maximum number of device paths ("sd" devices)

256

256 13

1,024 13,14

8,192 13,14

10,000 13,14

Required minimums

x86

256MB

256MB

512MB minimum/1 GB per logical CPU recommended

512MB minimum/1 GB per logical CPU recommended

N/A6

x86_64

256MB

256MB

512MB minimum/1 GB per logical CPU recommended

1GB minimum/1 GB per logical CPU recommended

1GB minimum/1 GB per logical CPU recommended22

Itanium 2

512MB

512MB

512MB/1 GB per logical CPU recommended

N/A6

N/A6

POWER

512MB

512MB

1GB minimum/2GB recommended

2GB minimum/2GB required per install

2GB minimum/2GB required per install

Minimum diskspace

800MB

800MB

1GB minimum/5GB recommended

1GB minimum/5GB recommended

10GB minimum/20GB recommended

File systems and storage limits

Ext3 - Maximum file size

2TB

2TB

2TB

2TB

2TB

Ext3 - Maximum file system size

2TB

8TB

16TB

16TB

16TB

Ext3 - Maximum subdirectories

32000

32000

32000

32000

32000

Ext3 - Maximum symlink depth

8

8

8

8

8

Ext3 - ACL support

Yes

Yes

Yes

Yes

Yes

Ext4 - Maximum file size

--

--

16TB

16TB

16TB

Ext4 - Maximum file system size

--

--

16TB [1EB]

16TB [1EB]

50TB [1EB]

Ext4 - Maximum subdirectories

--

--

65000/unlimited

65000/unlimited

65000/unlimited

Ext4 - Maximum symlink depth

--

--

8

8

8

Ext4 - ACL support

--

--

Yes

Yes

Yes

GFS - Maximum file size

2TB

16TB [8EB]

16TB [8EB]7

N/A

N/A

GFS - Maximum file system size

2TB

16TB [8EB]

16TB [8EB]7

N/A

N/A

GFS - Maximum subdirectories

--

unlimited

unlimited

--

--

GFS - Maximum symlink depth

--

unlimited

unlimited

--

--

GFS - ACL support

--

Yes

Yes

--

--

GFS2 - Maximum file size

--

--

100TB [8EB]

100TB [8EB]

100TB [8EB]

GFS2 - Maximum file system size

--

--

100TB [8EB]

100TB [8EB]

100TB [8EB]

GFS2 - Maximum subdirectories

--

--

--

unlimited

unlimited

GFS2 - Maximum symlink depth

--

--

--

unlimited

unlimited

GFS2 - ACL support

--

--

--

Yes

Yes

XFS - Maximum file size

--

--

100TB [8EB]

100TB [8EB]

500TB [8EB]

XFS - Maximum file system size

--

--

100TB [16EB]

300TB [16EB]19

500TB [16EB]

XFS - Maximum subdirectories

--

--

unlimited

unlimited

unlimited

XFS - Maximum symlink depth

--

--

8

8

8

XFS - ACL support

N/A

N/A

Yes

Yes

Yes

Maximum Boot LUN size (BIOS)

--

--

2TB

2TB10

2TB10

Maximum Boot LUN size (UEFI)

--

--

N/A

32bit (i686) - 2TB, 64bit - 16TB (tested limit)

50TB

Maximum x86 per-process virtual address space

Approx. 4GB

Approx. 4GB

Approx. 3GB4

Approx. 3GB4

N/A6

Maximum x86_64 per-process virtual address space

512GB

2TB

128TB

128TB

Kernel and OS features

Kernel foundation

Linux 2.4.21

Linux 2.6.9

Linux 2.6.18

2.6.32 - 2.6.34

3.10

Compiler/toolchain

GCC 3.2

GCC 3.4

GCC 4.1

GCC 4.4

GCC 4.8.2

Languages supported

10

15

19

22

22

NIAP/CC certified11

Yes (3+)

Yes (4+)

Yes (4+)

Yes (4+)

Under Evaluation (4+)

Common Criteria certified KVM11

--

--

Evaluated

Evaluated

Under Evaluation

IPv6

--

--

Ready Logo Phase 2

Ready Logo Phase 2

Under Evaluation

FIPS certified11

--

--

Yes (7 modules)

Yes (8 modules)

Under Evaluation (9 modules)

Common Operating Environment (COE) compliant

Yes

Yes

N/A

N/A

N/A

LSB-compliant

Yes - 1.3

Yes - 3

Yes - 3.1

Yes - 4.0

Under Evaluation (4.1)

GB18030

No

Yes

Yes

Yes

Yes

Client environment

Desktop GUI

Gnome 2.2

Gnome 2.8

Gnome 2.16

Gnome 2.28

Gnome 3.8

Graphics

XFree86

X.org

X.org 7.1.1

X.org 7.4

X.org 7.7

OpenOffice

V1.1

V1.1.2

V2.0.4 12

V3.2 12

LibreOffice V4.1.4 12

Gnome Evolution

V1.4

V2.0

V2.8.0

V2.28

V3.8.5

Default browser

Mozilla

Firefox

Firefox 1.5 12

Firefox 3.6 12

Firefox 24.5 12

Legend: Values are depicted as tested/supported [theoretical] above.

Notes:
1. Supported limits reflect the current state of system testing by Red Hat and its partners for mainstream hardware. Systems exceeding these supported limits may be included in the Hardware Catalog after joint testing between Red Hat and its partners. If they exceed the supported limits posted here, entries in the Hardware Catalog will include a reference to the details of the system-specific limits and are fully supported. In addition to supported limits reflecting hardware capability, there may be additional limits under the Red Hat Enterprise Linux subscription terms. Supported limits are subject to change as ongoing testing completes.
2. Red Hat defines a logical CPU as any schedulable entity. So every core/thread in a multicore/thread processor is a logical CPU.
3. The "SMP" kernel supports a maximum of 16GB of main memory. Systems with more than 16GB of main memory use the "Hugemem" kernel. In certain workload scenarios it may be advantageous to use the "Hugemem" kernel on systems with more than 12GB of main memory.
4. The x86 "Hugemem" kernel is not provided in Red Hat Enterprise Linux 5 or 6.
5. The architectural limits are based on the capabilities of the Red Hat Enterprise Linux kernel and the physical hardware. Red Hat Enterprise Linux 6 limit is based on 46-bit physical memory addressing. Red Hat Enterprise Linux 5 limit is based on 40-bit physical memory addressing. All system memory should be balanced across NUMA nodes in a NUMA-capable system.
6. Red Hat Enterprise Linux 6 does not include support for the Itanium 2 architecture. Red Hat Enterprise Linux 7 does not include support for the Itanium 2 and 32-bit x86 architectures.
7. If there are any 32-bit machines in the cluster, the maximum gfs file system size is 16TB. If all machines in the cluster are 64-bit, the maximum size is 8EB.
8. Officially support 125 CPUs across the entire machine.
9. Requires Intel EPT and AMD RVI technology support.
10. UEFI and GPT support required for more that 2TB boot LUN support (https://access.redhat.com/kb/docs/DOC-16981).
11. Get security certification details.
12. Firefox, Thunderbird, and OpenOffice applications will be updated during the life cycle.
13. Larger numbers are possible, depending on testing and support by the specific hardware vendor. For example, EMC supports up to 8,192 device paths on Red Hat Enterprise Linux 5. Consult your hardware vendor to determine their limit, and confirm with your Red Hat support representative. In no case will Red Hat support a limit that exceeds the limit supported by the hardware vendor.
14. It may be necessary to increase certain driver parameters to reach these limits. Consult with your Red Hat support representative.
15. Red Hat Enterprise Linux 6.7 is required for support of 12TB of RAM. Red Hat Enterprise Linux 6.6 can support up to 6TB of RAM. Previous versions of Red Hat Enterprise Linux 6, starting with Red Hat Enterprise Linux 6.3, support up to 3TB of RAM. Versions of Red Hat Enterprise Linux prior to Red Hat Enterprise Linux 6.3 support up to 1TB of RAM.
16. Red Hat Enterprise Linux 7.2 is required for support of 12TB of RAM. Red Hat Enterprise Linux 7.1 can support up to 6TB of RAM. Previous versions of Red Hat Enterprise Linux 7 (i.e. Red Hat Enterprise Linux 7.0) support up to 3TB of RAM.
17. Red Hat Enterprise Linux 6.7 or newer is required for 448 CPU support. The previous maximum supported CPU count for earlier versions was 288 CPUs.
18. Red Hat Enterprise Linux 7.3 with errata kernel 3.10.0-514.26.2.el7 or newer is required for 768 CPU support. Red Hat Enterprise Linux 7.2 with errata kernel 3.10.0-327.18.2.el7 or newer is required for 576 CPU support. Red Hat Enterprise Linux 7.2 or newer is required for 384 CPU support. The previous maximum supported CPU count for earlier versions was 288 CPUs. Also, for 7.2 or newer, please refer to the following Red Hat Knowledgebase article: Memory swap occurs while the pagecache is reclaimed.
19. Red Hat Enterprise Linux 6.8 or newer is required for 300TB XFS filesystem support on RHEL 6.x. The previous maximum supported XFS filesystem size in RHEL 6.7 and earlier was 100TB.
20. Red Hat Enterprise Linux 7.5 or newer, Red Hat Enterprise Linux 7.4 Extended Update Support (EUS) kernel version 3.10.0-693.25.2.el7 or newer, or Red Hat Enterprise Linux 7.3 Extended Update Support (EUS) kernel version 3.10.0-514.48.1.el7 or newer is required for 768 CPU support. The previous maximum supported CPU count for earlier update releases or EUS kernels of Red Hat Enterprise Linux 7 was 192 CPUs.
21. Red Hat Enterprise Linux 7.5 or newer, Red Hat Enterprise Linux 7.4 Extended Update Support (EUS) kernel version 3.10.0-693.25.2.el7 or newer, or Red Hat Enterprise Linux 7.3 Extended Update Support (EUS) kernel version 3.10.0-514.48.1.el7 or newer is required for support of 32TB of RAM. Previous update releases or EUS kernels of Red Hat Enterprise Linux 7 could support up to 2TB of RAM.
22. Network / PXE install requires at least 1.5 GB of RAM for the install procedure only.

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